Get students experiments, groups, and cohorts

TNL-498

openedx/core/djangoapps/user_api/partition_schemes.py

@@ -15,15 +15,16 @@ class RandomUserPartitionScheme(object):
     RANDOM = random.Random()
 
     @classmethod
-    def get_group_for_user(cls, course_id, user, user_partition, track_function=None):
+    def get_group_for_user(cls, course_id, user, user_partition, assign=True, track_function=None):
         """
         Returns the group from the specified user position to which the user is assigned.
-        If the user has not yet been assigned, a group will be randomly chosen for them.
+        If the user has not yet been assigned, a group will be randomly chosen for them if assign flag is True.
         """
         partition_key = cls._key_for_partition(user_partition)
         group_id = course_tag_api.get_course_tag(user, course_id, partition_key)
         group = user_partition.get_group(int(group_id)) if not group_id is None else None
-        if group is None:
+
+        if group is None and assign:
             if not user_partition.groups:
                 raise UserPartitionError('Cannot assign user to an empty user partition')
 

openedx/core/djangoapps/user_api/tests/test_partition_schemes.py

@@ -58,6 +58,24 @@ class TestRandomUserPartitionScheme(PartitionTestCase):
             group2_id = RandomUserPartitionScheme.get_group_for_user(self.MOCK_COURSE_ID, self.user, self.user_partition)
             self.assertEqual(group1_id, group2_id)
 
+    def test_get_group_for_user_with_assign(self):
+        """
+        Make sure get_group_for_user returns None if no group is already
+        assigned to a user instead of assigning/creating a group automatically
+        """
+        # We should not get any group because assign is False which will
+        # protect us from automatically creating a group for user
+        group = RandomUserPartitionScheme.get_group_for_user(
+            self.MOCK_COURSE_ID, self.user, self.user_partition, assign=False
+        )
+
+        self.assertIsNone(group)
+
+        # We should get a group automatically assigned to user
+        group = RandomUserPartitionScheme.get_group_for_user(self.MOCK_COURSE_ID, self.user, self.user_partition)
+
+        self.assertIsNotNone(group)
+
     def test_empty_partition(self):
         empty_partition = UserPartition(
             self.TEST_ID,